Probably the best known and third largest, of all the constellations, Ursa Major is also known as the Plough, Big Dipper, the Great Bear or Saucepan. It is used as a kind of Celestial signpost. If you draw an imaginary line from Merak through Dubhe and continue five times as far as Dubhe is from Merak, you will find Polaris, the Pole Star. If you now draw an imaginary line along the handle of the dipper and continue the arc across the sky, this will lead you Arcturus in the constellation Boötes. If you continue further, you will reach Spica in Virgo. Following the other two stars in the bowl of the dipper (Megrez and Phecda) down below the bowl takes you to Regulus, the bright star in Leo The spiral galaxies M101, M81 and M82 are to be found in Ursa Major. All are fairly easily seen in binoculars and small telescopes under good conditions. M81 is one of the brightest galaxies in the sky at magnitude 7. It is tilted at an angle to us, and, thus, appears slightly elliptical. Mizar is a well known double star, magnitude 2.3. Its companion is Alcor, magnitude 4.0. The two can be seen unaided with keen eyesight, and are easily separated with binoculars and small telescopes.Canes Venatici is a minor constellation and represents two dogs, Asterion & Chara chasing the Great Bear, Ursa Major around the heavens, and held on a lead by Boötes. The constellation contains many galaxies. The most well known being M51, the Whirlpool, a lovely spiral galaxy seen face on, best viewed with binoculars. M51 was one of Charles Messier’s original discoveries but it was the 3rd Earl of Ross from Birr Castle, Ireland, who was the first person to discover the spiral structure and made a very careful and acurate painting. Therefore, M51 is sometimes referenced as Rosse’s Galaxy or Lord Rosse’s “Question Mark”.
Other noteable objects are: M3, a rich globular cluster located midway between Cor Caroli and Arcturus, & M94, a compact spiral galaxy.